Standard surgical procedures require the surgical site to be disinfected prior to surgery. Effective pre-operative cleansing of the surgical site is critical to reducing the risk of infection to the patient. Pre-operative skin preparation is therefore as important as the prophylactic antibiotic treatment in control of infection.
Microorganisms on the skin can be transient or resident. Transient microorganisms lie on the surface of the skin, while resident microorganisms are found at deeper sites in the skin, for example, in skin hair follicles. During pre-operative procedures it is desirable to initially kill the microorganisms relatively quickly to reduce the length of time to prepare the patient for surgery. It is also important that the antimicrobial activity can be sustained throughout the surgical procedure by the skin-preparation.
Iodophore has been widely used as a disinfectant and as a pre-operative skin preparation. Pre-operative skin-preparation solutions such as PVP-I scrub and paint solutions are commonly used to disinfect the surgical site prior to surgery. Existing iodophore skin-preparation solutions typically include iodine, surfactant and a buffer system to provide appropriate pH in an aqueous system. The solutions typically contain an active ingredient of 7.5% to 10.0% povidone iodine. These concentrations of iodine are desirable to provide effective and extended killing of microorganisms.
Aqueous iodophore skin-preparations tend to run on the patient's body to areas that don't require disinfection. For example, between the patient and the operating table, and may accumulate on those undesired areas where the iodine can cause skin irritation in certain patients. Gel has been added to povidone iodine to reduce running of the skin-preparation. It provides a film texture allowing the antimicrobial to localize at the desirable surgical incision site without reducing the thickness of iodine from the site. Typically, the iodine content of the gel form is about 10.0% w/v or the effect of antimicrobial activity would not be prominent.
Although iodine gel provides the advantage as described, it kills microorganisms at a relative slower rate than other antimicrobial agents such as alcohol. Alcohol has long been recognized as a disinfectant which reduces bacteria, fungi, and some viruses at a great speed. However, alcohol alone evaporates quickly. The disinfection action of alcohol does not continue once the alcohol evaporates from the skin. Accordingly, alcohol alone lacks a prolonged ability to disinfect the surgical site. Iodine skin-preparations are usually applied to a patient in a multi-step process. The typical recommended procedure calls for a 7.5% w/v iodine preparation to be scrubbed on the patient for approximately 2 minutes and then blotted dry. The 7.5% iodine preparation is reapplied to the patient and scrubbed on the patient again for approximately 2 minutes, and blotted dry. A 10.0% w/v iodine solution is then painted onto the patient. During pre-surgical skin-preparation, a shorter time period of application is desirable for practical reasons.
The present invention by adding alcohol to PVP-I gel provides benefits of a rapid and sustained antimicrobial activity, localization of skin-preparation by forming a film on the skin, and a single-step of short time period application. The invention also provides an opportunity to lower the iodine concentration requirement thus reducing the incidence of irritation of certain patients. All these characteristics, in combination, are not described in the precedent skin-preparations.